Content providers will pay content distribution systems different rates based on audience size, with higher rates per content presentation or view for larger audiences. With unicast Internet delivery, instances of content presentation may be accurately measured, with content delivery servers accurately reporting the number of client devices to which any item of content was delivered. While it may be easy to assume that every instance of delivery results in a user paying attention to or actively consuming the content, this may not always be true. A user's attention may be drawn elsewhere such that they do not actively consume the content, or the user may leave the immediate area without pausing or stopping the media stream resulting in presentation of content to an empty room. Content providers may not wish to pay for such presentations.
Additionally, content selection systems for personalized or custom content delivery may use presentation statistics to determine which users or demographics are interested in what types of content. Assuming that all users are engaged or interested in all content that is delivered to their client devices may exaggerate the actual interest rate in some items, resulting in incorrect selections and user dissatisfaction with the content selection system.